Translating means for television impulses



May 1937- A. P, RICHARDS 2,080,927

TRANSLATING MEANS FOR TELEVISION IMPULSES Filed Feb. 29, 1932 4 Sheets-Sheet l A. P. RICHARDS 2,080,927

TRANSLATING MEANS FOR TELEVISION IMPULSES 4 Sheets-Sheet 2 May 18, 1937.

Filed Feb. 29, 1932 May 18, 1937. A. P. RICHARDS TRANSLATING MEANS FOR TELEVISION IMPULSES Filed Feb. 29, 1932 4 Sheets-Sheet 3 fig-a3 May 18, 1937. A. P. RICHARDS TRANSLATING MEANS FOR TELEVISION IMPULSES Filed Feb. 29, 1932 '4 Sheets-Sheet .4

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s fl a v NM W P. N M A 9 Y 6 B a 7 9 f R r r 1 27 m 78 @F w Patented May 18, 1937 UNITED STATES PATENT OFFICE TRAN SLATING MEANS FOR TELEVISION IMPULSES 4 Claims.

My invention is addressed to the provision of simplified means for translating the several types of impulses which may be employed in a system for the continuous transmission of light impulses forming a picture or scene. An object of my invention is the provision of responsive means of a reflecting character, whereby in combination with a source of light I may produce upon a screen a projected composite image.

Consequently an object of my invention is the provision of means whereby a member bearing a reflective surface may be caused to move in accordance with a predetermined plan, so that a beam of light from a source which may be stationary is caused continuously to traverse an image space.

It is my object to accomplish this by magnetic means.

It thus appears as one of my objects to do away with scanning devices employing synchronous actuators and moving members having one or more series of apertures.

My invention is also concerned with the control of my translation apparatus in accordance with a plurality of established frequencies which may be generated at the place where the translation apparatus is employed, but may be and preferably will be generated at the sending station and transmitted thereby, so that the instrumentalities at the sending station control the synchronism of my device.

These and other objects of my invention which will be pointed out hereinafter or will be apparent to one skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts of which I shall now describe a preferred embodiment. It will be understood, of course, that modifications may be made in this embodiment without departing 40 from the spirit of my invention, the essential novelty of which I shall set forth in the claims.

- Reference is now made to the drawings, wherein:

Fig. 1 is a perspective view of the aforesaid 45 preferred embodiment.

Fig. 2 is a front elevation thereof.

Fig. 3 is a vertical sectional view taken along the center line of the drawing in Fig. 2.

Fig. 4 is an elevation of the mounting means for my reflective element.

Fig. 5 is a plan view of my device.

Fig. 6 is a partial horizontal section through the device as shown in Fig. 2, the said section .being taken along thelines 6, 6.

Fig. '7 is a sectional view of the high frequency core assembly.

Fig. 8 is a plan view of the low frequency core assembly.

Fig. 9 is a vertical sectional view of the low frequency core assembly.

Fig. 10 is a diagram showing the action of my device in the projection step.

Briefly, in the practice of my invention, I provide a member having a reflective surface, and I impart to this member rocking motions in a plurality of planes, whereby a beam of light reflected upon the member is caused to traverse an image space in a desired mannen In the particular embodiment of my invention which I shall now describe, there is a mirror so mounted as to be capable of vibratory movement about a vertical axis. It is likewise so mounted as to permit a concurrent vibration about a horizontal axis. Specifically, I may provide a magnetic field structure having air gaps, and I may mount in these air gaps a supporting structure which comprises essentially a coil of one loop. This structure supports the reflecting element, and when a suitable pulsating current is applied thereto, will move in the field much like the coil of a galvanometer moves in its field. Thus the vibratory motion is constantly applied to the reflecting device. Next I provide another actuator, which may also comprise magnetic field means and a coil or armature adaptedito move with respect thereto, and by positioning this second actuator so that the direction of movement of the armature or coil is transverse to the direction of movement of the loop aforesaid, and by connecting it operatively with said mirror or reflecting device I may cause said mirror to vibrate in another plane. By choosing different frequencies for these components of motion Imay vibrate my mirror in such a way that it will cause a beam of light continuously to traverse an image space.

Referring now to Fig. 3, I show abase I, upon which I mount anadjustable standard 2. This standard bears a field structure which I have designated broadly at 3. The construction of this field structure in section is shown in Fig. '7, wherein itis seen to comprise a back member 4, sidewise extending arms 5 and l, and members 8 and 9, bearing pole pieces I0 and II. Between the pole pieces there is shown an auxiliary core member [2, so positioned that between it and the pole pieces l0 and .II there are provided narrow air gaps I3 and. The supporting loopto which I have referred is positioned so that the vertically extending wires which .it comprises lie in these narrow air gaps; and since the loop vibrates about a central vertical axis, the central portion of the supplementary core member I 2 is made cylindrical in cross section.

Since it is convenient to mount my mirror at a point approximately centrally located in the field structure, the member I2 is divided as will most clearly be seen in Fig. 2, where the upper portion of it is indicated at l2, and the lower portion at i2a. Pieces of brass .(or other nonmagnetic material) I5 and I6 join the portions 8 and 9 of the field structure, and to these pieces I the members [2 and I2a are attached by screws,

or otherwise, as shown.

A spider-like supporting structure hereinafter to be described, lies in the space between the members [2 and Ho, and between themembers 8 and 9, which may be notched as at I! and I8 to accommodate the sidewise arms of the spider.

In Fig. 4 I have shown a mirror I9, which is pivoted upon pins 20' and 2| set in eyelets 22 and 23. The longitudinal portions 24 and 25 of the wire loop aforesaid pass through these eyelets, but are electrically insulated therefrom by fine washers 26 and 21 of some wear-resisting insulating substance such as ivory, which will permit some sliding of the wires 25 and 24 with respect thereto, while maintaining a frictional engagement.

The wires 25 and 24 are fastened to insulatin grommets 28 and 29 in a lower bar 39. They likewise pass through grommets 3| and 32 in an upper metallic bar 33, and are connected by an integral portion 34. The bars 3|] and 33 are mounted by means of vertically extending wires 35 and 36 centrally attached thereto, and these, in turn, are held in mounting meanspresently to be described. The'wire members 24, 34 and 25 form an open loop, to which current connections may be made as by means of wires 31 and 38. It will be clear that any vibratory motion of the loop about the pivot members 35 and 36 will cause the mirror to vibrate about a vertical axis.

The field structure members 5 and 1 of course, bear appropriate exciting coils 39 and 49.

In order to understand the remainder of my structure a description of the field portion of the other prime mover is now necessary, since it also forms a part of the supporting devices. To the base I I attach (Figs. 1 and 3) a field structure indicated generally at 4|. This is, in my preferred embodiment, very much like the familiar field core structure of the dynamic loud speaker. As indicated in section, in Fig. 9 there is a base member 42, side arms 43 and 44, and a top member 45. A central post or pole 46 is provided, the upper end of which passes through a perforation in the top plate 45, leaving an annular air gap 41. An exciting coil 48 surrounds this central post.

A pair of brackets 49 and 59 are fastenedupon the top plate 45. They support the forward ends of members 8 and 9 of the upper field structure, to which end they maybe provided with adjustable supporting connections 5! and 52. I also attach a bracket 53 to the member I6. This bracket bears an arm 54 perforated to receive the wire 35, and provided with a set screw 55 to clamp it tightly. This assembly .is clearly shown in Fig. 3.

To the members 8 and 9 I attach at the top a horizontal plate 56. This plate has an upturned portion 57, to which a bracket 58 is attached. The bracket hasa turned over portion 'ating in the air gap 41.

59. It is slotted vertically to receive a screw 69 by which an angle bracket BI is slidably held thereto. This bracket is likewise perforated to receive the end of the wire 35 and is provided with a clamping set screw 62. An adjusting screw 63 is threaded into the bracket member 6| and operates through a hole in the member 59. By adjusting this screw, as will be evident, any desired tension may be placed upon the loop member (Fig. 4) which controls vibration of the mirror about its vertical axis. The wires 35 and 36 will preferably be made of resilient metal of non-magnetic character; and since they are rigidly clamped, it will be seen that the loop aforesaid vibrates against a tension in these Wires produced by twisting them, which tension normally tends to hold the loop centered between the pole pieces land H and the members l2 and I212. By adjusting the vertical tension upon wires 35 and 36, this tension may be controlled so that it counterbalances the inertia of the assembly, including the mirror l9.

As to the mirror itself, it may be of silvered glass held in an aluminum or other light frame 19a, or it may be of polished metal. It will ordinarily be a plane mirror, but it may be made concave or convex, asdesired.

The mirror is also pivoted as by means of light pins 64 and 65 to a spider member having arms 66, 61, 68 and 69. The arms 68 and 69 extend horizontally and are pivoted as at I0 and H to a U-shaped bracket 12. The pivot pins 94 and 65 tend to establish a vertical axis of rotation of the mirror l9; and the pivot members ll and 19 establish a horizontal axis for the spider aforesaid, these pivot members being so located that they lie in the plane of the pivot members 29 and 2| when the mirror is at rest. Any rocking of the spider member about the pivot pins 19 and H, however, will tend to impart to the mirror a vibratory motion about a horizontal axis, which motion may be concurrent with, and in any event does not interrupt the motion of said mirror about a vertical or nearly vertical axis as determined by the movements of the loop aforesaid. The spider arm 69 bears an extension 13, to which a vertically reciprocating operating arm 14 is pivoted. This arm rocks the spider.

The spider may be centered by opposed springs 15 and 16 (Figs. 1 and 3) attached to the arm 13 and attached at their outer ends to vertically guided brackets 11 and I9, slidably mounted upon the brass arms l5 and i6, and controlled, as shown, by thumb screws 19 and 89. tering means may, of course, be employed.

The operating rod 14 is connected, as by means of a cap member 8!, to an armature coil 82 oper- The leads from the coil 82 may conveniently be brought out to binding posts 83 and 84, mounted upon an insulating plate 85 upon the member 45. The leads from the coil 48 may conveniently be brought out to binding posts 86 and El, located upon a fiber plate 89 mounted upon the other end of the member 45. A third insulating plate 99 may be mounted in a position of convenient access and bear posts or terminals 9| and 92, to which the leads 3'! and 36 are attached. Binding posts 93 and 94 may be mounted upon a plate or plates 95 and 96, and connected with the leads from coils 39 and 49.

This completes a general description of the features of the preferred embodiment. A number of modifications may be made inthe general Other censtructure and arrangement of the several parts without departing from the spirit of my invention. Thus instead of being located below the upper field structure, the assembly M may be located in an appropriate space between the coils 39 and 40. Again, instead of providing for the transmission of vibratory motion in one direction to the mirror by a rod M, I may secure vibration about a horizontal axis, by connecting to the spider aforesaid a loop much like that loop which imparts motion to the mirror about a vertical axis. Such loop will be located in an appropriate field structure similar to the field structure employed for the loop which I have illustrated. These and many other modifications of my invention may be made by those skilled in the art without departing from the scope of the appended claims.

In operation, I prefer to excite my several field structures with direct current from a suitable source, it being desirable to provide as concentrated a field as is possible, to which end the windings will be apportioned to the value of the current available. Now if I excite the loop formed of the wire members 2 3, 34 and 25 by means of a suitable alternating current it will be obvious that this loop will tend to vibrate about a vertical axis determined by the wires 35 and 36, and that it will carry with it and impart a vibratory motion to the mirror. If a beam of light be caused to impinge upon the mirror, it will be reflected therefrom in a series of horizontal vibrations and may be caused to describe a line upon a screen. A satisfactory rate of vibration is in the neighborhood of 600 cycles per second, but I am, of course, not restricted to any particular rate of vibration.

If now a vibratory motion at a difierent frequency be imparted to the rod 14, the mirror will be given a component of motion about a horizontal axis, and the beam of light refiected thereby will tend to move vertically as well as horizontally. A satisfactory rate of vibration for the rod It is in the neighborhood of Ill cycles per second, but I am not restricted to this frequency any more than to the other frequency hereinabove mentioned. However, if the frequencies are properly proportioned a beam of light reflected as in Fig. 10 from a source indicated at 91 through a suitable lens 98 by the mirror l9, may be caused to scan or traverse a screen as shown at 99 in a plurality of lines N10. The particular wave forms chosen will determine the nature and disposition of the lines Hill. A pure sine wave is not a particularly advantageous wave form to use, although for the higher frequency this does not make so much difierence. I have found that the inertia and tension of the various members may be so proportioned as to give, in response to a sine wave, a motion which is not purely a sine motion, and it is possible to traverse the screen with light lines in the horizontal direction which are almost horizontal and. parallel. A sine wave for the slower frequency is less desirable because it will tend to make the horizontal light lines lie closely together at the top and bottom of the image space. For this reason I prefer to provide a very much more sharply peaked wave form at least for actuating the slower frequency actuator. Such a wave form may be provided by a suitably wound generator, or in other known ways. As indicated hereinabove, I prefer to provide a suitable generator or generators at the sending station, impressing both of the frequencies, and also the light intensity impulses upon a suitable carrier wave. The sound maybe impressed upon a different carrier wave if desired;

Of course my apparatus is not restricted to use in radio transmission, but isequally suitable forthe wired transmission of intelligence. It is adapted to give within the limits of the power of the light source an image of as large a size as desired. The amplitude, however, of the impulses which control the scanning vibrations of the mirror should remain constant, since it will be apparent that otherwise the picture size will vary. A smaller amplitude of impressed signal will produce a smaller picture, assuming that the amplitude of the two frequencies varies together. If one varies while the other does not, of course, a distorted picture will result. Consequently in use for receiving radio transmission my device should be employed with known automatic volume control means.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a scanning device, a field structure having interspaced pole pieces, magneticmeans between said pole pieces leaving interspaced air gaps, a loop of conductive wire having a leg normally located in each of said air gaps, a mirror pivoted to the legs of said loop along an axis transverse to said loop, a spider pivoted to an external support in the said first mentioned axis when said mirror is in normal or central position, a pivoting connection between said mirror and said spider along an axis transverse to said first mentioned axis, means for making current connection with said loop, and means for oscillating said spider.

2. In a scanning device, a field structure having interspaced pole pieces, magnetic means between said pole pieces leaving interspaced air gaps, a loop of conductive wire having a leg normally located in each of said air gaps, a mirror pivoted to the legs; of said loop along an axis transverse to said loop, a spider pivoted to an external support in the said first mentioned axis when said mirror is in normal'or central position, a pivoting connection between said mirror and said spider along an axis transverse to said first mentioned axis, means for making current connection with said loop, and means for oscillating said spider, said means comprising a magnetic field structure, an armature, and a connection between said armature and said spider.

3. In a scanning device, a field structure having interspaced pole pieces, magnetic means between said pole pieces leaving interspaced air gaps, a loop of conductive wire having a leg normally located in each of said air gaps, a mirror pivoted to the legs of said loop along an axis transverse to said loop, a spider pivoted to an external support in the said first mentioned axis when said mirror is in normal or central position, a pivoting connection between said mirror and said spider along an axis transverse to said firstmentioned axis, means for making current connection with said loop, means for oscillating said spider, said means comprising a tical air gap, an armatureflof the pivoted coil type mounted in said air gap, a second field structure having a central pole and an annular pole thereabout, an armature of the moving coil type located in an air gap between said poles, a mirror horizontally pivoted to said first mentioned armature, a spider horizontally pivoted to a support, said mirror vertically pivoted to said spider, and an operative; connection between said spider and said second armature.

AMYLE P. RICHARDS. 

